Artemis stepped over the same mossy root for the third time that morning. He knew it by the split in the bark. The Whispering Woods were bending him back to the same small clearing, the way they bent anyone who walked in carrying a wanted face in their head. His was a woman with dark hair and light eyes, and a laugh he had been chasing since childhood. He sat down on the flat stone at the center and admitted, out loud, that he was lost. That was when he saw it near his boot — a curved, jewel-bright pedal he had dropped on his first pass through, now glowing faintly in the leaf litter. He picked it up. The trees went quiet. A narrow path opened between two trunks that had, a moment ago, stood shoulder to shoulder. Artemis stood, pocketed the strange thing, and walked through before the woods could change their mind.

The new path held for an hour before it ended at a wall of brambles. Artemis stopped and listened. No birds. No wind. He reached into his pocket and drew out the petal that had brought him this far. It was the last one. Its glow had faded from jewel-bright to a tired ember, and the curved edges had gone soft, as if the petal were melting from the inside. He held it up. The brambles did not move. He pressed it flat against his palm and waited. A thin warmth answered him, and then nothing. He sat down in the leaves and thought it through. One petal, almost spent. One wall of thorns. If he used the petal here and the path was short, he would be stranded again with nothing. If he saved it, he would be stranded here. He turned the petal between his fingers and watched its light dim further. He had organized his life around chasing a face he could not prove existed. He could at least be honest about the arithmetic in front of him now. He stood and held the petal toward the brambles. The light flared once and went out. The brambles parted, slowly, into a narrow gap. Artemis stepped through before it could close. On the other side the trees thinned into a small clearing, and at the center stood a single flower he had never seen before. It was taller than his knee. Its layered petals glowed from within in pink and gold and pale blue, steady and bright, the way his spent petal had glowed when he first found it. He walked to it and knelt. Up close he could see the petals were the same shape as the one in his pocket. A whole flower of them. Enough to open many passages. He let out a breath he had been holding since the brambles. He reached to pick a petal and stopped. The flower's light pulsed once under his hand, like a small animal noticing him. Above its center, the air folded. A pale shape lifted out of the bloom — a butterfly with wings the color of the petals — and hung there, watching him. Artemis did not move. He had come into these woods to find a woman, and he had told himself he would listen first before he spoke. He lowered his hand and waited. The butterfly drifted once around his head and settled on the flower's tallest petal, folding its wings. It was guarding the bloom. He could not simply take what he needed. Whatever came next, he would have to ask.

Artemis stayed on his knees in front of the flower. The butterfly rested on the tallest petal, wings folded, watching him without moving. He understood he had to offer something. He also understood he did not know what this creature would want. Guess wrong, and it might close the bloom against him for good. He had used his last petal to reach this clearing. If the flower sealed, he would not leave these woods. He went through his pockets slowly. A folding knife. A length of cord. A handful of coins that meant nothing here. Near the bottom he found a small cluster of milkweed blossoms he had picked two days ago without thinking, pink and purple, still soft. He almost held them up. Then he stopped. He was about to offer a guard flower another flower, cut and dying in his pocket. He set the blossoms in the leaves beside his knee and left them there. He thought about what he actually carried that no one else could. He thought about the dream. The woman with dark hair and light eyes. Her laugh. The one where she was crying. He had never told it to anyone in years. He looked up at the butterfly. "I don't have anything worth this," he said. "I can tell you why I'm here. That's all I have left." And he told it. The child's dream. The face that would not leave him. The night she cried and he woke certain it was real. The women he had failed because none of them were her. The fear that she belonged to someone else. He spoke until his voice ran out, and then he stopped. The butterfly lifted from the petal. It circled him once, slow, close enough that he felt the air move at his ear. Then it landed on the back of his hand. The flower's light pulsed, and one petal at its outer edge loosened and fell into his open palm. Just one. The butterfly stepped onto the petal, folded its wings, and stayed. Artemis closed his fingers around both. He understood the trade. He had been given passage, and a witness. He stood up. The clearing was quiet. He had what he needed to keep going, and something now traveled with him that could be offended, lost, or asked again. He left the milkweed in the leaves and walked toward the trees.

Artemis walked between the trees with the petal in one pocket and the butterfly on his sleeve. The path narrowed into a corridor of low branches, then opened. He stopped at the edge of the opening. The butterfly did not lift from his sleeve. He held out his hand to coax it forward. It stayed where it was and pressed its wings flat against the cloth. He looked at what lay ahead. The ground past the tree line had gone pale and cracked, split into long fissures that ran toward a ravine. A broken bridge hung over the gap, planks snapped in the middle, ropes frayed at the posts. Beyond the bridge, a dark cave mouth opened in the rock, framed by stacked stones. The forest did not reach across the cracked ground. No roots, no green. The air above the fissures shimmered the way air shimmers over a hot stove. Artemis took one step forward to test it. The butterfly shut its wings tighter and did not move with him. He stopped. He stood there a long time. The cave looked like the kind of place a path was supposed to lead. He had spent a year following thinner signs than this. He thought about the bargain. He had given the butterfly the only thing he kept hidden, and in return it had agreed to travel with him. A witness, he had decided. He had not asked what a witness was for. Now it was telling him, with its small body, that the bridge would not hold and the cave would not give him back. If he crossed anyway, he would be calling its warning worthless. He would be calling the trade worthless. He stepped back from the tree line. The butterfly loosened its grip on his sleeve. He turned along the edge of the cracked ground and began to walk parallel to the ravine, looking for another way down or around. After a few minutes the butterfly lifted from his sleeve and flew ahead of him, low, steady, leading. He followed. He had not crossed, and he was not lost yet. He had also used the only guide he had, and he understood now that it would not take him everywhere he wanted to go. Somewhere past the ravine was a direction it would not let him try. He kept walking and watched the wings move ahead of him in the gray light.

Artemis followed the butterfly along the ravine's edge until the cracked ground gave way to moss and roots again. The trees closed in. The path bent away from the cave and dropped into a hollow where the light went green. He had begun to trust the small wings ahead of him when he heard the sound. It came from the trees to his left, soft and steady. A woman, weeping. The butterfly did not slow. It flew on along its chosen line, low and certain. Artemis stopped on the path. He listened. The crying did not stop. He thought of the dream that had sent him into these woods, the woman whose face he could not stop seeing. He thought of every date he had cut short because he had already decided. He owed someone an apology. He did not know if it was her. He stepped off the path toward the sound. The butterfly flew three slow circles above him, then settled on a low branch and waited. Artemis pushed through the ferns and found a girl, not the woman he was looking for, sitting against a tree with her knees drawn up. She held a tarnished silver locket open in both hands. The portrait inside showed a child's face wrapped in a pale shawl. She did not look up when he knelt. He asked what she had lost. She said the locket had belonged to her sister, and she could not find the way home. Artemis sat with her. He did not promise to lead her out. He told her about the butterfly that would guide him only where it chose, and said the same small wings might help her if she asked. He helped her stand. He walked her back to the path. The butterfly lifted from the branch and flew a short way ahead, then waited. It did not refuse her. The girl wiped her face and followed the wings. Artemis followed behind. He had lost nothing of his guide's patience, and he had learned that the bargain bent further than he had feared. The path he wanted was still ahead, and now he walked it with two.

The path narrowed past the ravine's edge and split into three quiet hollows. The butterfly slowed above Artemis's shoulder and hung there, wings beating small and uncertain. The girl stopped behind him with the tarnished locket pressed to her chest. Artemis looked at the three openings. Each one bent out of sight after a few steps. He had learned by now that the woods closed passages behind travelers who chose wrong. He waited for the butterfly to pick. It did not pick. He knelt to see the ground. The left hollow smelled of wet stone. The middle one showed a low mossy arch of gray rock, half-swallowed by ferns. The right hollow was darker and drew a faint cold breath. He asked the butterfly which way. The butterfly circled once and landed on the girl's wrist, and stayed there. A small green creature stepped out from the roots of the middle arch. It stood no taller than Artemis's knee. Leafy sprigs curled from its head and hands. It did not speak. It lifted one leafy hand toward the left hollow and shook its head. Then it lifted the other hand toward the right hollow and shook its head again. It pointed at the mossy arch and stepped aside. Artemis did not move yet. He had trusted a guide once and been led away from a cave that would have killed him. He had also left a path once and found a grieving child. He looked at the girl. She was watching the small creature with her mouth open. He asked her what she thought. She said the little thing looked scared for them. That was enough. He thanked the sprig-creature and walked toward the arch. As he passed under the stones, something bright dropped from the top of the arch and landed in his palm. It was a key. The shaft was pale metal. The head was worked into curling shapes with a blue butterfly set at its center. He closed his hand around it. Above them, a pale bird with blue wings lifted from the crown of the arch and flew ahead down the new path, slow enough to follow. Behind them, the two other hollows folded shut. The ferns knitted together. The stone shifted. In seconds there was only forest where the openings had been. The girl made a small sound. Artemis did not turn around. He had chosen, and the woods had answered, and the answer could not be taken back. He opened his hand again and looked at the key. He did not know what it opened. He knew the butterfly had given it, and that somewhere ahead was a lock. For the first time since the dream that sent him here, he felt he was being led toward a door instead of a face. He followed the blue-winged bird down the path, the girl close behind him, the butterfly light on her wrist.

The blue-winged bird kept a slow pace ahead of them. Artemis followed with the key closed in his fist. The girl walked at his elbow. The butterfly rode on her wrist and did not lift off. The path narrowed and the trees thinned, and after a while the ground under his boots turned pale and hard. He stopped at the edge of it. The forest floor gave way to a wide flat of cracked earth. Deep splits ran through the crust in every direction. Some were narrow. Some were wide enough to swallow a leg. The bird flew straight out across the cracks and landed on a low stone at the far side, where a dark cave mouth opened between rough boulders. Artemis could see no lock from here. Only the cave, and the bird waiting. "It wants us to cross," the girl said. She looked at the fissures. "I can jump the small ones." Artemis opened his hand. The key sat there, pale metal, the blue butterfly bright at its head. He thought about the cave. He thought about the last cave, and how the butterfly had refused it, and how he had listened. He looked at the butterfly on the girl's wrist. It did not move. It did not warn him back. He took that as the closest thing to permission he was going to get. He stepped onto the cracked ground. It held. He picked a line between two wide splits and moved slow. The girl came behind him, light on her feet. Halfway across, a crust broke under his heel and his boot dropped six inches into a fissure. He caught himself on his hands. The girl grabbed the back of his coat. He pulled his foot free and did not look down again. They kept going. The bird waited. At the cave mouth he saw it. A cluster of pink and purple blossoms grew from a crack in the stone beside the opening. In the middle of the flowers, half hidden, was an iron plate set into the rock. A keyhole. Small. Shaped for a key with a butterfly head. Artemis knelt. He brushed the petals aside with two fingers. He fit the key into the hole. It turned. Something in the stone gave a low click, and a seam opened along the base of the cave mouth, and cool air pushed out from inside. The girl let out a breath. The butterfly lifted from her wrist and hovered near the seam, wings quick now. Artemis stayed on one knee. He had guessed right. The key belonged here. Whatever lay past the opening was what the woods had been leading him toward since the arch. He pulled the key free and stood. The bird stepped aside on its stone. Artemis looked into the dark of the cave and could not see the end of it. He did not know what waited inside. He only knew the door was open now, and behind him the cracked ground would not carry them back.

Artemis stood at the open cave mouth and listened. Cool air came out steady against his face. Beyond the first few feet of stone, the dark went flat and total. He could not see the far wall. He could not see the floor. The bird had flown up to a ledge and would not follow. The butterfly hovered at his shoulder, wings slow. He turned to the girl. "Stay close," he said. "Hand on my coat." He took three steps in and the light behind them shrank to a pale slot. He put a hand on the wall. The stone was cold and wet. He slid his boot forward and felt the floor tilt down. The girl's fingers tightened at his back. He could not tell if the passage went straight or curved. He could not tell if there was a drop. He stopped. "I can't see," he said. He said it plain because there was no use pretending. "If we walk blind, one of us falls, or you let go and I lose you." The butterfly lifted off his shoulder. It flew a short way ahead and stopped. Its wings, when they moved, showed a faint blue edge he had not noticed in daylight. Not enough to light the floor. He watched it hover. He thought of the bargain. He thought of what he still had to give. He knelt and opened his palm. The butterfly key lay across it, the small blue wings at its head bright even in the dim. He held it out. "Take the rest," he said to the butterfly. "Whatever's left of what I owe. I need to see." He did not know if it would work. He only knew the key had done its one job and the woods asked payment for everything. The butterfly settled on the key. Its wings opened wide and held. Light came out of them, cold and steady, enough to show ten feet of floor and the low curve of the roof and a narrow path that dropped away to the left into nothing. The girl made a small sound. Artemis closed his hand around the key. The butterfly rose with it, keeping the light. He stood. "Behind me," he said. The girl kept her grip on his coat. They walked. The light moved with the butterfly, and the drop stayed at their left, and the floor under his boots held. Somewhere ahead the passage bent. He did not know what was around the bend. He knew he could see it when he got there, and that the key in his hand was warm now, and lighter, as if something had been drawn out of it and given back as light.

The passage bent and opened into a wider chamber. Cold air moved across Artemis's face, and he heard water before he saw it. The butterfly's light spread over a still, black pool that filled the cave floor from wall to wall. A narrow ledge ran along the right side. On the far shore, something small and pale flickered above the surface. The girl let go of his coat and pointed. "Look." It was another butterfly, or something like one. White wings, thin as paper. It skimmed the water and rose, skimmed and rose. Their own butterfly lifted from the key in his palm and drifted after it, drawn. "Wait," Artemis said. He stepped onto the ledge. The stone was slick. The girl followed, close at his shoulder. The pale thing dipped low over the middle of the pool. Their butterfly followed, and the light went with it, and Artemis leaned to keep it in sight. The ledge gave under his boot. He went in sideways. The cold hit his chest and drove the air out of him. He heard the girl cry out, and then a smaller splash, and then nothing but water in his ears. He kicked. His coat pulled him down. He clawed at the wall and found no grip, only wet stone that slid under his fingers. His head broke the surface. He saw the girl thrashing an arm's length away, mouth open, hair over her eyes. "Hold on to me," he tried to say, and swallowed water. He had never learned to swim. Neither had she. He caught her sleeve. She caught his collar. They pulled each other down. The light above them shrank. His chest burned. He kicked once more and his boot found nothing. The girl's grip loosened. He thought, absurdly, of the woman with dark hair, and of how he had not found her yet, and of how sorry he was. Then the water lit up. A silver shape swept over the pool — a bat, blind-eyed, wings shining like oil on water. Behind it came a boy. He was small, black-haired, barefoot, and he moved through the water like he had been born in it. He hooked an arm under the girl's arms and kicked her toward the ledge. He came back for Artemis. His hand closed on Artemis's wrist and pulled. Artemis's knees struck stone. He dragged himself up, coughing, and hauled the girl the rest of the way. She lay on her side, breathing in ragged pulls. The boy climbed out last and sat back on his heels, calm as if he had done this before. "You're Marcus," the girl said, when she could speak. Her voice cracked. "You're my sister's — " The boy nodded once. He looked at Artemis. "The bat knows the way out," he said. "But the pool isn't done with you yet."